Incorporating noise and/or jitter into waveform generation

Abstract

Methods and apparatus disclosed herein operate, for example, to derive a non-ideal received signal from an ideal signal, to compute, from the non-ideal received signal, at least one probability density function of amplitude and time values representing deviations from the ideal signal, to derive at least one amplitude noise component and at least one timing jitter component from the at least one probability density function, and to generate a non-ideal waveform by applying the at least one amplitude noise component and the at least one timing jitter component to an ideal waveform.

What is claimed is: 
     
       1. A computer-implemented method comprising:
 using one or more hardware-based processors coupled to a memory to perform at least a portion of one or more of the following, 
 deriving a non-ideal received signal from an ideal signal; 
 computing, from the non-ideal received signal, at least one probability density function of amplitude and time values representing deviations from the ideal signal; 
 deriving at least one amplitude noise component and at least one timing jitter component from the at least one probability density function; and 
 generating, using the one or more hardware-based processors, a non-ideal waveform by applying the at least one amplitude noise component and the at least one timing jitter component to an ideal waveform. 
 
     
     
       2. The computer-implemented method of  claim 1 , wherein the non-ideal received signal comprises a non-ideal pulse response of a transmission channel. 
     
     
       3. The computer-implemented method of  claim 2 , wherein computing the at least one probability density function from the non-ideal received signal comprises sampling the non-ideal pulse response to form samples, and recursively convolving the samples. 
     
     
       4. The computer-implemented method of  claim 1 , wherein the non-ideal pulse response is derived from a non-ideal step response. 
     
     
       5. The computer-implemented method of  claim 1 , further comprising generating, from the non-ideal received signal, an eye diagram including the at least one probability density function. 
     
     
       6. The computer-implemented method of  claim 1 , further comprising convolving the at least one probability density function with sampled voltages to generate modified voltage-based probability density functions. 
     
     
       7. The computer-implemented method of  claim 6 , further comprising mathematically convolving additional amplitude noise into the modified voltage-based probability density functions. 
     
     
       8. The computer-implemented method of  claim 1 , further comprising mathematically convolving additional timing jitter into the at least one probability density function. 
     
     
       9. The computer-implemented method of  claim 1 , wherein at least one of an amplitude noise vector or a timing vector is derived from the at least one probability density function. 
     
     
       10. The computer-implemented method of  claim 9 , wherein an element from the amplitude noise vector is selected randomly to form the amplitude noise component, and wherein an element from the timing jitter vector is selected randomly to form the timing jitter component. 
     
     
       11. A system comprising:
 a memory; 
 one or more hardware-based processors coupled to the memory; 
 a derivation module to derive a non-ideal received signal from an ideal signal; 
 a computation module to compute, from the non-ideal received signal, at least one probability density function of amplitude and time values representing deviations from the ideal signal; and 
 a generation module, using the one or more hardware-based processors, to generate a non-ideal waveform by applying at least one amplitude noise component and at least one timing jitter component to an ideal waveform, the at least one amplitude noise component and the at least one timing jitter component being derived from the at least one probability density function. 
 
     
     
       12. The system of  claim 11 , further comprising a recordation module to record the at least one probability density function of amplitude and time values. 
     
     
       13. A computer-implemented method comprising:
 using one or more hardware-based processors coupled to a memory device to perform at least a portion of one or more of the following, 
 recording a plurality of received bit patterns from a non-ideal received signal as a plurality of recorded bit patterns, each bit pattern of the plurality of received bit patterns comprising a bit of interest and a region of influence; 
 measuring the bit of interest in each bit pattern of the plurality of received bit patterns to determine a plurality of voltage and time values representing deviations from an ideal signal; 
 obtaining an ideal waveform comprising a bit pattern that includes a bit of interest and a region of influence; 
 comparing the bit pattern of the ideal waveform to the plurality of recorded bit patterns to determine a matching bit pattern; and 
 generating a non-ideal waveform by applying at least one value of the plurality of voltage and time values from the matching bit pattern to the bit of interest of the bit pattern of the ideal waveform. 
 
     
     
       14. The computer-implemented method of  claim 13 , further comprising storing each value of the plurality of voltage and time values in a table. 
     
     
       15. The computer-implemented method of  claim 13 , further comprising averaging each value of the plurality of voltage and time values. 
     
     
       16. The computer-implemented method of  claim 13 , further comprising storing the plurality of voltage values in a table. 
     
     
       17. The computer-implemented method of  claim 13 , further comprising the plurality of time values in a table. 
     
     
       18. The computer-implemented method of  claim 13 , further comprising mathematically convolving amplitude noise into the plurality of voltage values, and mathematically convolving timing jitter into the plurality of time values. 
     
     
       19. A system comprising:
 a memory; 
 one or more hardware-based processors coupled to the memory; 
 a recordation module to record a plurality of received bit patterns as a plurality of recorded bit patterns, each of the plurality of recorded bit patterns comprising a bit of interest and a region of influence from a non-ideal received signal; 
 a measurement module to measure the bit of interest in each bit pattern of the plurality of received bit patterns to determine a plurality of voltage and time values representing deviations from an ideal signal; 
 a comparison module to compare a bit pattern of an ideal waveform to the plurality of recorded bit patterns to determine a matching bit pattern, the bit pattern of the ideal waveform comprising a bit of interest and a region of influence; and 
 a generation module, using the one or more hardware-based processors, to generate a non-ideal waveform by applying at least one value of the plurality of voltage and time values from the matching bit pattern to the bit of interest of the bit pattern of the ideal waveform. 
 
     
     
       20. The system of  claim 19 , wherein the one or more hardware-based processors are configured to store the plurality of voltage and time values for the bit of interest in the memory.